Now that Memorial Day weekend is over, Americans are eagerly entering the summer vacation season. Most of us can look forward to a few days — or even weeks — of hard-earned rest and relaxation. But a new report by the Center for Economic and Policy Research shows that not everyone will be so lucky. That's because the U.S. remains the only advanced economy on Planet Earth that doesn't guarantee all workers at least a minimal number of paid days off. Here's a look, by the numbers, at just how stingy the nation's businesses can be with vacation time:

23Percentage of American workers who get no paid vacation time. The same percentage gets no paid holidays, either.

35Percentage of part-time U.S. workers who get paid vacation.

91Percentage of full-time U.S. workers entitled to vacation as part of their compensation.

0Legally mandated paid holidays in the U.S.

20Developed nations — out of 21 — where all workers are guaranteed paid vacation. The U.S. is the lone holdout.

8.1Average number of vacation days U.S. full-time employees get after a year on the job, according to the Bureau of Labor Statistics.